The Tropic of Capricorn is one of the five major circles of latitude that mark maps of the Earth. As of 2014[update], its latitude is 23° 26' 14.440" [1] south of the Equator, but it is very gradually moving northward, currently at the rate of 0.47 arcseconds, or 15 metres, per year.[2]

The position of the Tropic of Capricorn is not fixed, but rather it varies in a complex manner over time; see under circles of latitude for information.

As with the Tropic of Cancer, most places along the Tropic of Capricorn have arid or semi-arid climates, though with the Tropic of Capricorn this unfavourable environmental state is exacerbated by the fact that in Australia and Southern Africa tectonic activity and glaciation have been largely absent since the Carboniferous 300 million years ago, so that the aridity is compounded by extremely infertile soils. This results in a generally scrubby vegetation, with perennial grasslands occurring in less infertile cracking clay soils. In Australia, areas on the Tropic have some of the most variable rainfall in the world[3] and thus even the wetter areas cannot be generally farmed since irrigation sources invariably dry up in drought years. In southern Africa, where rainfall is more reliable, farming is possible though yields are low even with fertilisers.

In South America, whilst in the continental cratons soils are almost as old as in Australia and Southern Africa, the presence of the geologically young and evolving Andes means that this region is on the western side of the subtropical anticyclones and thus receives warm and humid air from the Atlantic Ocean. As a result, areas in Brazil adjacent to the Tropic are extremely important agricultural regions, producing large quantities of crops such as coffee, and the natural rainforest vegetation has been entirely cleared. In and west of the Andes, however, the Humboldt Current makes conditions extremely arid, creating one of the driest deserts in the world, so that no glaciers exist between Volcán Sajama at 18˚30'S and Cerro Tres Cruces at 27˚S.[4] Vegetation here is almost non-existent, though on the eastern slopes of the Andes rainfall is adequate for rainfed agriculture.

Around the world[edit]

Starting at the Prime Meridian and heading eastwards, the Tropic of Capricorn passes through:

List of countries entirely south of the Tropic of Capricorn[edit]

As the major portion of earth's land is located in the Northern Hemisphere there are only four countries entirely south of the Tropic of Capricorn (there are 74 countries entirely north of the Tropic of Cancer):

Name[edit]

The Tropic of Capricorn is so named because when the Sun reaches the zenith at this latitude, it is entering the tropical sign of Capricorn (Southern or December solstice). When it was named, about 2,000 years ago, the sun was also in the direction of the constellationCapricornus (capricorn is Latin for goat horn) at the December solstice. In modern times the sun appears in the constellation Sagittarius during this time. The change is due to precession of the equinoxes. The word "tropic" itself comes from the Greek trope (τροπή), meaning turn, change in direction or circumstances, referring to the fact that the sun appears to "turn back" at the solstices.

Cultural significance[edit]

In India, the day of Sun entering the zodiacal belt Capricorn is celebrated as Makara Sankranti festival. Tropic of Capricorn is called Makara Vrutta in Indian languages. It should be noted here that the Indian astronomical calendar is not based on the Western sidereal system but has a differential lag. Hence, the festival is celebrated on either of 14 or 15 Jan every year, when, as per the Indian astronomical calendar, the Sun enters the Capricorn sign.